Heals in Tiberium
Floaters are a species of strange, jellyfish-like creatures that began to grow more and more prevalent as time went on and as the first phase of the Second Tiberium War was drawing to a close. Floaters - as their name implies - float over the battlefield, propelling themselves with clouds of Tiberium-saturated gas. The gas is highly dangerous to infantry, potentially turning them into visceroids. Worse, Floaters seem to be capable of generating intense electrical charges and currents that they often use to attack vehicles; the Floater will typically latch onto the vehicle to both tear it apart with its tentacles and send vast quantities of electricity through the target.
As with most mutated lifeforms, Floaters were highly aggressive and represented a significant threat to almost anything in their vicinity, and worse, they were surprisingly resilient for what some might dismiss as a floating bag of gas; it could take several heavy vehicles to bring just one of them down, and a single floater was more than a match for a GDI Titan or a Nod Tick Tank. In at least one instance GDI forces actually had to coordinate an armored defense to protect and evacuate civilians due to the threat of attacks by groups of such creatures.
Furthermore, the floaters' electric attack, which is used when in contact with the target, is extremely effective against both vehicles and structures. The floater can even prevent the vehicle it was attacking from firing. It was not seen after the Firestorm Crisis for unknown reasons. It seems likely that the Floater was simply an evolutionary dead-end, and the creatures were not capable of reproducing or perhaps even surviving for long periods of time; with tiberium-based toxins killing off many forms of ocean life, it may simply be that no more Floaters ever 'evolved' after the originals died out, as no creature provided a suitable template for them to develop from.
It is unknown what manner of creature was mutated into the floater. Currently the best estimates would be the jellyfish, as there are many obvious similarities between this species and the floater.